At noonJosh Duhamel agreed to pose in his BVDs for the Life as We Know It poster—his new flick with Katherine Heigl—only if Warner Bros. agreed to fix his gam in post: “I was like, ‘OK dude,'” he tells Robin Milling, “‘I’ll do the underwear. But please make my right calf look a little bit bigger!'”

At 8 PMArtists on Demand swoops in on Sara Canning, who plays Jenna Sommers on The Vampire Diaries—and who began her career playing Nicky Hilton in the 2008 TV flick Paparazzi Princess: The Paris Hilton Story. Plus: Comedian Chris Valenti.

At 4 PM In the Mix host Donna Sam gives it up for Tichina Arnold, who had us roaring as Pamela James on Martin before tackling the role of young (TV) Chris Rock’s mom on Everybody Hates Chris. The funny lady will chat about her latest creative outlet—belting out pop tunes.

At 7 PMRandom Talk Radio’sInga Prater cuts loose with the Conan O’Brien Band, who are promoting a Sept. 19 fundraiser for a new documentary about Chuck Berry’s late piano player, Johnnie Johnson. The guys will also fill us in on (shhh) Conan’s new late-night TBS show, launching Nov. 8.

At 1130 AMAround the Water Cooler host Jonathan Hall talks with Patricia Tocalino, the lead scientist on a U.S. Geological Survey report on contaminants in well water used as sources of tap water. Find out who may be affected—and what can we do about this potential danger.